METHODS AND SYSTEMS FOR GENERATING PERCOLATED ROCK PHYSICS MODELS FOR PREDICTING PERMEABILITY AND PETROPHYSICAL QUANTITIES

摘要

The disclosure relates to a computer-implemented method of generating a percolated rock physics model with interacting pore scheme. Input data relating to observed porosity values, corresponding observed shear velocity or compressional velocity values, and relative proportions of mineral components of a composite matrix comprising a host material, are obtained. The method comprises, for each combination of observed porosity and observed shear velocity or compressional velocity, iteratively: incrementing a pore aspect ratio; determining an initial dry frame compressional modulus and an initial dry frame shear modulus using the observed porosity, the observed velocity and the pore aspect ratio; modifying the initial dry frame compressional modulus using a compressional percolation function and modifying the initial dry frame shear modulus using a shear percolation function; computing a shear velocity or a compressional velocity from the modified shear modulus or the modified compressional modulus; and continuing to iterate until the computed shear velocity matches the observed shear velocity (within a predefined error), or the computed compressional velocity matches the observed compressional velocity (within a predefined error). The method may comprise determining a permeability value through specific pore surface area during each iteration over the pore aspect ratio and pore connectivity. Respective modified compressional modulus, modified shear modulus, permeability and pore aspect ratio values after a last one of said iterations represent mappings from porosity and velocity to wet and dry compressional modulus, shear modulus, permeability and pore aspect ratio in the rock physics model.